[MPlayer-users] mencoder options for NTSC television

[Martin Collins]

On Tue, 14 Jan 2003 10:20:58 -0600
Lance Simmons <lance at lsimmons.net> wrote:

> 1.  NTSC resolution:  one message when I use mencoder says
> 
>  Supported sizes: 48x32 => 768x480
> 
>  Does that mean that the height and width I choose have to preserve
>  that ratio?

No. NTSC is 640x480 so you could try that. Some of that width may be
useless though. Keep both dimensions divisible by 16 for the encoder.

> 2. vbitrate:  higher is better, right?

Up to a point, and from the point of view of quality. Lower bitrate
means smaller files but lower quality.

> How do I decide what vbitrate to use?  I've been using 16000,
> and the results look good.

I'm sure they do :-) I have found going much above 3000 is pointless
for PAL. Do some experiments. Add vpass=1 to your -lavcopts then run
TOOLS/countquant.pl < divx2pass.log
after encoding something. You have maximum quality when q=2 is 100%
Aim for 95% as you get diminishing returns bitrate / filesize.

> What's the benefit of going lower?

Smaller files.

> 3. postprocessing:  what kind of postprocessing is best?  How do I
> decide whether to crop or not?  Where in the documentation is there
> a clear description of what the various postprocessing options do? 

Nowhere, at least in rc2. doc/mplayer/tech/vop.txt is the closest.
I am currently using:
-vop eq=7:14,pp=lb,unsharp=l3x3:1.5
Any -vop options will slow down your encoding.

Martin